Steam-boiler



4 Sheets Sheet 1.

(No Model.)

0. P. MARSHALL.

STEAM BOILER.

No. 383,364. Patented May 22, 1888.

N PEITERS Pholuljlhugmphnr, Washingion, n. c.

(N08 Model.) 4 Sheets-Sheet 2.

O. P. MARSHALL.

STEAM BOILER. No. 383,864. PatentedMay 22, 1888.

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(No Model.) 4 Sheets-Sheet 3.

O. P. MARSHALL.

STEAM BOILER. No. 383,364 Patented May-Z2, 1888.

N, PETERS, Phulo-Lilhogmphcr, Washington, (LC.

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O. P. MARSHALL.

STEAM BOILER. No. 383,364. PatentedMaJy 22, 1888.

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NITED STATES PATENT rricn,

CHARLES P. MARSHALL, OF lVlEMPHIS, TENNESSEE.

STEANl BOILER.

SPECIFICATION forming part of Letters Patent No. 383,364, dated May 22, 1888.

Application filed February 17 1888. Serial No. 264,382.

To all whom it may concern:

Be it known that I, CHARLES P. MARSHALL, a citizen of the United States, residing at Memphis, in the county of Shelby and State of Tennessee, have invented certain new and useful Improvements in Steam-Boilers, of which the following is such a full, clear, and exact specification as to enable those skilled in the art to which it appertains to make and use the same.

My invention relates to that class of boilers commonly known as return-fine boilers, and it has for its object to provide a boiler of this nature which will be of novel construction and effective in operation.

Referring to the accompanying drawings, which form an important part of this applica tion, Figure I represents a side view of my boiler in vertical section. Fig. II represents a front view of the same in vertical section. Fig. III is a perspective view of the breeching and smoke-box, hereinafter fully described. Fig. IV is a transverse sectional view of the boiler, taken on the line IV IV, Fig. I. Fig. V is a vertical section of a modified form.

The boiler proper, or that portion for accommodating the Water and steam, is formed by the two shells or drums 1 2, arranged concentrically one within the other, and the inner one being of smaller diameter than the other. The inner shell, 1, is shorter than the outer shell, and it is capped with a fiuering, 3, whose cross-section is in the form of a compound curve, its inner edge being curved downwardly and secured to the said inner shell, while its outer edge curves upwardly and is secured to a vertical ring, 4.,which is situated within about one inch of the outer shell, 2, and supports at its upper edge the curved crown-sheet 5, and thus a large heating-surfaceis formed directly under the steam-space 6. The two shells thus arranged form an annular water-leg,which is provided at its bottom with a flue-ring, 7, and also with a number of smokeiiues, 8, which are arranged vertically within said leg at short intervals apart-and entirely around the same, with the exception of that space which is directly over the furnace-door 9, and have their upper and lower ends expanded in the flue-rings 3 and 7, respectively.

In the form represented by Figs. I and II of the drawings, and as best illustrated by the (No model.)

former figure, the inner shell, 1, of the boiler extends downwardly considerably below the lower flue-ring, 7, which supports. the boiler and forms the inner wall, 11, of the smokebox, and also forms the ash-pit below the grate when the form of smoke-box and breeching shown in Fig. III is used. This smoke-box and breeching is preferably composed of sheetiron, and is provided with doors 12 13 14 15 on all sides to facilitate the cleaning of the smoke-fines, and also to permit the removal of the soot and cinders which necessarily collect in the smokebox. The top of the smoke-box and breeching is formed with an annular opening whose diameter is nearly equal to that of the outer shell, 2, of the boiler, and the edge of which opening is provided with an upwardly-projecting flange, 16,which latter,when the downwardly-projecting extension of the shell 1 is placed within the annular opening in the smoke-box and rests upon a suitable foundation or flooring, 17, engages on the inside of a downwardly-projecting flange, 18, formed by the joint between the flueplate 7 and the outer shell, 2, of the boiler, the wall 11 and the smoke'box of course being of the same height, so as the latter will be subjected to but little or no pressure from the boiler, and at the same time the flanges l6 and 18 will be held coincided, and thus produce a smoke-tight joint between the parts.

The inner wall, 11, of the smoke-box is provided with a door or an opening, 19, which corresponds with a door, 20, in the outer wall of the said box, and the two openings are connected by a passageway, 21. (Shown in dotted lines in Fig. III and in longitudinal section in Fig. II.) These two openings, as is of course understood, facilitate the removal of the ashes, and the passage-way connecting said openings prevents the smoke from entering the ash-pit or from escaping through the doorway in the outer wall when the door 20 is opened. Located diametrically opposite the door 20 is an opening, 22, with which the smoke-pipe 23 com municates, and is secured to the outer wall of the smoke-box by any suitable means. The

crown-sheet 5 of the fire-box is supported by vertical tie or suspension rods 24, riveted therein and in the top sheet of the boiler, and the shells 1 and 2 and ring 4. are tied together by transverse rods 25. By this construction it will be seen that the smoke and other products of combustion rising from the fire-box will strike the curved crown-sheet 5, and in consequence thereof be deflected toward the curved flue-ring 3,which will direct said products into the flues-S, which transmit the heat from the products of combustion to the water and empty the said products into the smokebox, from whencethe latter are drawn by the stack.

The form represented by Fig. Vis provided with an outerjacket, 27,which has secured at its top the crown-sheet 28, in the center of which latter the stack 29 is secured. At the base of this jacket is an outwardly-swelled portion, 30, which projects outwardly over the flange 16 ofthe smoke-box, and is secured to the outer shell, 2, of the boiler by means of a flanged ring, 31, provided with a number of perforations, 32, for the passage of smoke and other products of combustion from the smoke-box into the space formed by the outer jacket. It

will be seen that this outer jacket will keep the exterior of the boiler hot and at the same time serve as a smoke-flue. This is a very neat and preferable form of the invention.

Having thus described my invention, the following is what I claim as new therein and desire to secure by Letters Patent:

In a boiler, the combination, with the furnace having a combustion-chamber and inner shell, 1, and the outer shell, 2, the former having the extension 11, adapted to sustain the entire weight of the boiler, the flue-ring 7 ,joining said shells, at box surrounding said extension and having an opening in its top of less diameter than said box, an upwardly-projecting flange, 16, at the edge ofsaid opening. and a downwardly-projecting flange, 18, on the shell 2, surrounding and coinciding with flange 16, and adapted to contact with the top of said box and fines connecting said combustionchamber and box, as set forth.

CHARLES P. MARSHALL.

Witnesses:

ASBET MOOASLET, JOHN B. GLoUeH. 

